Akonadi TODO

The following list contains the things which need to be done for Akonadi.

Note: The person noted in the "Contact" column is not necessarily the one implementing that feature, but the one who can tell you what to do and how to help, i.e. you can also contribute to those tasks ;-)

There is also a more detailed page about bugs and missing features of things that are currently ported here.

Core

KDE 4.1 / Akonadi 1.0

Urgent tasks that need to be finished for the KDE 4.1 release (May 19th):

Those items don't belong to the same collection, rather they are located in different collections

[mailto: <>]

TO DO

CollectionFetchJob/ItemFetchJob should be able to retrieve entities by flags/mimetype

This is problematic with change notifications, as they have to know about the filtering with the \Seen flag as well.
This type of filtering would be possible with full Nepomuk interface though. We don't want yet another query language here. The plan is to fix the nepomuk agent and use that as semi-public interface for now.

Resource status overview (this should list all resources existing in KDE3 or already under development for Akonadi):

Resource

Retrieve Collections

Retrieve Items

Change Collections

Change Items

Configuration

Notes

iCal

yes (4)

yes (1) (2)

no

yes

yes

remote file support, file watching with conflict handling

vCard

yes (4)

yes (1) (2)

no

yes

yes

remote file support, file watching with conflict handling

maildir

yes (1) (4)

yes (1) (2)

?

?

yes

mbox

no

no

no

no

no

not started yet, code exists in KMail

IMAP

yes (1) (4)?

yes (1) (2)

no

no

no

code exists in kio_imap4 and Mailody, support for extensions: quota, ACL, annotations missing, what about Kolab and Scalix?

NNTP

yes (4)

yes (2)

n/a

n/a

yes

Needs support for local collection names and collection hierarchy

Local Bookmarks

?

?

?

?

(3)

Code in akonadi/resources

OpenChange

?

?

?

?

?

Code in akonadi/resources

Facebook

?

?

?

?

?

Code in playground/pim

del.icio.us

?

?

?

yes

no

Code in playground/pim

KABC

yes(6)

yes

no

yes

yes

KCal

yes(6)

yes

yes(7)

yes

yes

only full sync supported currently, need optimization

does not yet honor cache policy

still relies on QSettings for configuration and/or doesn't provide configuration over D-Bus

does not yet provide correct access control settings

only adding new items, not changing existing ones

availability of child collections depend on whether the KResource plugin has subresources

child collections can be added or removed if the KCal plugin can have subresources

KResource Migration Status

Everything without migration support is implicitly converted to use the compat bridge currently.

KABC migration status

KResource

Feature equivalent agent

Migration support

Notes

directory

vCard dir in development

file

vCard file

4.2

binary format no longer supported, migrated to compat bridge instead

groupdav

groupwise

kolab

ldapkio

net

vCard file

TODO

scalix

slox

xmlrpc

KCal Migration Status

KResource

Feature equivalent agent

Migration support

Notes

blog

bugzilla

groupdav

groupwise

kabc (birthday)

birthdays

4.3

kolab

localdir

local

iCal file

4.2

remote

iCal file

TODO

remote supports different URLs for upload and download, the iCal file agent doesn't, is this needed at all?

featureplan

probably obsolete since we don't use the XML featureplan anymore

scalix

slox

xmlrpc

Akonadi Braindump

Ideas/notes etc. on various open issues in Akonadi.

Akonadi Standard Actions

Idea: Have something like KStandardAction for Akonadi that not only includes the representation of the action but also its state management and the actual operations. Like libakonadi that should be splitted into a generic, type-independent part and be extensible for type-specific actions. This will enable code sharing among many applications and guarantee consistent actions everywhere.

Deployment issues

Multiple access: Should multiple Akonadi instances' mysqlds access a single set of data files the mysql will likely corrupt the data. This can happen in any NFS+YP installation where users can log onto any machine and access shared homes. MySQL relies on filesystem locking to prevent multiple access. MySQL multiple instance docu.

AppArmor: Distros' AppArmor profiles prevent MySQL from writing outside its defined data directory (usually /var/lib/mysql). This is a problem at least with *buntu and openSUSE. These will need to be adapted. It is possible to daisy-chain profiles so that MySQL started by Akonadi receives a different profile to MySQL running standalone. An empty profile has all rights. Another possibility is to adapt the general MySQL profile so it can write to ${XDG_DATA_HOME}/akonadi(usually ${HOME/}.local/share/akonadi). Both support for profile chaining and ${HOME} may depend on the version of AppArmor installed. What about SELinux?

Backup: MySQL data files should not be backed up without telling the mysqld process, otherwise a corrupt backup will be made. LOCK TABLES and FLUSH TABLES at the least. A dump can be made or mysqlhotbackup may be used in some circumstances. We should consider sysadmins' backup techniques when planning/promoting Akonadi, as a simple rsync cronjob with running Akonadi will not work. MySQL backup advice.

Search & Virtual Collections

KMail Breakdown Plan

The current plan is to put some parts of KMail into a stand-alone
library, independent of KMail. This increases code reuse (for example, the message composer could be shared with Mailody) and makes the code a lot easier to maintain and to port to Akonadi.

Akonadi FAQ

This FAQ primarily deals with technical and design questions, if you have questions about using Akonadi (such as "I get error X when starting Akonadi"), please refer to userbase.kde.org/Akonadi.

Where do I find the Akonadi config files?

~/.config/akonadi/

Where does Akonadi store my data?

Akonadi merely acts as a cache for your data, the actual content stays where it has always been, .ics/.vcf/MBOX files, local maildirs, IMAP- and groupware servers. There is only a limited amount of data stored exclusively in Akonadi:

Data not supported by the corresponding backends, such as email flags in case of maildir/mbox. This is comparable to KMail's binary index files stored alongside these files in pre-Akonadi times.

Internal meta-data used by application or resources, such as information about the last synchronization with a backend or translated folder names.

Data that has been changed while the corresponding backend has been offline and has not yet been uploaded.

Which DBMS does Akonadi use?

So far only MySQL. There is some work on PostgreSQL support going on though. Basically, every database that is supported by QtSQL can be used, requiring minimal changes in the code at most. However, not all of them provide the features needed by Akonadi (see next two questions).

Why not use sqlite?

We tried. Really. It can't handle the concurrent access very well, in the best case this means very slow operations, but we've also seen deadlocks and failing transactions. Once that's fixed in sqlite, adjusting Akonadi to use it again instead of MySQL is no problem.

Why not use MySQL/Embedded?

We tried that as well, there are two reasons for not using it: No support for the InnoDB engine (which we need for transaction support) and poor availability (only OpenSUSE provided usable packages, needed a patched QSQL driver).

Do I need a running MySQL server?

No. Akonadi starts its own local MySQL server (unless configured otherwise, see next question). All you need is having the 'mysqld' binary installed at runtime (usually found in the mysql-server package of your distribution).

Can Akonadi use a normal MySQL server running on my system?

Yes, it can. You find the corresponding settings in ~/.config/akonadi/akonadiserverrc.

Can I connect multiple Akonadi instances to the same database to share my data between different machines?

That does not work unfortunately. Akonadi does not store all relevant data in the database but also uses the file system for configuration and large payload data for example. Also, there is no mechanism to ensure multiple instances have exactly the same version and exactly the same agents and plug-ins installed etc., all of which would be necessary to work on the same database. Finally, there is no notification system to inform the other instances about changes which endangers consistency since the Akonadi server contains internal caches of data in the database. If you want multiple instances to synchronize, use a groupware server (not as bad as it sounds, Kolab for example works with many normal IMAP servers).

If you try this despite the warnings, be aware that there is no safety mechanism in place to prevent you from doing that and you will likely mess up your data in funny ways.

I don't like a database server because of backups/running on NFS/etc.

See section "Deployment Issues" above, we are aware of that and working on it. Some of these, like backup/restore are already implemented. But please be aware that most of this issues also existed before (eg. with KMail's custom binary indexes).

Can a single Akonadi instance be used by multiple users?

No. There has to be one Akonadi server instance per user. However, it is possible to use a shared database server.

Can I access the Akonadi server on a remote machine?

No. Akonadi is not a groupware server. It's a local cache only.

What's the differences between Akonadi and EDS?

EDS (Evolution Data Server) is limited to contacts and calendar data, Akonadi is type-independent. Especially, Akonadi is designed to also handle high-volume data such as email. Akonadi and EDS also differ largely in their access protocol on a technical level (Corba/D-Bus vs. local socket with IMAP-like protocol/D-Bus) and also on a protocol level (type specific vs. generic).

How do I create a collection?

From the developers point of view, there is Akonadi::CollectionCreateJob for that, from the users point of view, most applications allow that, eg. Mailody or akonadiconsole.

However, there is one limitation: Top-level collections can only be created by resources, not by normal applications. The reason for that is that every object (collection or item) is supposed to have an owning resource, that is a resource that is responsible for storing and retrieving that object. There is an ongoing discussion to remove this restriction though.

So, if you want to create a collection eg. for testing purposes, add a resource first. Most Akonadi applications offer an option to do that, a module for KControl is planned as well.

How do I disable automatic migration from KDE's traditional framework?

The migration tool is controlled by standard KDE configuration file called kres-migratorrc.

Distributors or system administrators wanting to disable the automatism will probably want to that globally, e.g. by editing the installed default configuration file, or by using KDE's configuration hierachy and using a profile config between that and the user level.

The quickest way to deactivate it for one user account only is to use KDE's kwriteconfig tool to set the respective configration value with a simple copy&paste of the following command:

Please note that at some point KDE applications such as Kontact, KOrganizer, KMail will be using Akonadi directly, at which point migration either has to be enabled or performed manually.

As of KDE 4.4 (and its development releases and when building from SVN trunk) this already applies to KAddressBook and KMail's address book access.

How do I completely disable Akonadi startup?

Warning

If you already have applications natively using Akonadi, you of course can't disable Akonadi startup. KAddressBook (as of KDE 4.4 and its test versions), Mailody, KMail (as of KDE 4.4 and its test versions for address book related things) and KPilot are applications that are already based on Akonadi.

Other applications, like KOrganizer, are not based on Akonadi yet, at the time of writing. Instead, they use the old KResource framework for storing contacts, calendars and notes.
During the KDE 4.2 beta time, these KResources were automatically migrated to Akonadi-based KResources, the so-called Akonadi compatibility resources. Therefore, applications like KOrganizer would use Akonadi indirectly through KResources, and therefore would start the Akonadi server when being started.

If Akonadi doesn't start up correctly for you, the following should help you to disable Akonadi startup and use your old KResources again.

First, disable automatic migration like described in the above FAQ entry.
Then, open System Settings, go to the Advanced tab and open the KDE Resources config panel. There, you can configure which type of KResources are used for contacts, calendars and notes. If the migration to Akonadi was successful, you'll probably only see the Akonadi Compatibility Resource as an active resource, and all others disabled.

What is the relation between Akonadi and OpenSync?

Akonadi and OpenSync focus on different aspects and complement each other. Akonadi provides a unified way to access PIM data for applications and a framework to implement powerful connectors to varies data sources. OpenSync focus is on syncing two sets of PIM data.

An Akonadi plugin for OpenSync is currently under development, allowing to sync PIM data available through Akonadi with any other system supported by OpenSync, especially mobile phones.

When should I use Akonadi?

More precisely, when should you use for your application specific data instead of eg. just using a local file directly.

Akonadi is especially useful when you need one the following:

Different backends for your data, like eg. a local file and a remote server. Akonadi provides a unified interface for application developers to access your data independent of the actual backend.

Caching and change replay of remote data. Akonadi has support for that built in, giving you free offline support for any remote backend.

Desktop-wide sharing of your data. As soon as more than one application (say your main applications and a plasmoid) accesses the same data you need to deal with locking, conflict detection, change notifications, etc. - or let Akonadi do that for you.

However, if you are just looking for a simple way to store your application data without needing one of the above, using Akonadi usually means more implementation work for relatively little gain.

Akonadi needs too much space in my home directory!

An empty, unused Akonadi database needs about 100 Mb of disk space. This is due to the MySQL InnoDB log files which work similar to a journal in a modern file system. These files are constant in size and independent of the actual data stored in Akonadi. The default size is optimized for performance on average desktop hardware where the use of 100 Mb of disk space is no problem. In other cases, such as multi-user systems or embedded devices, this default might not be optimal though.

The default size can be configured, globally or per-user. The global configuration file can be found in $PREFIX/share/config/akonadi/mysql-global.conf, the per-user file is in ~/.config/akonadi/mysql-local.conf and overwrites settings of the global file. In any of these files, you can change the settings innodb_log_file_size and assign it a smaller value than the default (64M).

For this setting to take effect you need to restart Akonadi. With older Akonadi versions (<=1.1.1) you might need to manually remove the InnoDB log files from ~/.local/share/akonadi/db_data for this change to take effect. The log files do not contain data after a clean shutdown and thus can safely be removed while Akonadi is not running.

An alternative approach especially for multi-user systems might be the use of a single, global MySQL server instance.

My Akonadi resource seems to randomly hang/stop working!

A very common problem of resources based on Akonadi::ResourceBase are "unguarded exit paths" from one of the methods you have reimplemented there. See the following example:

In case of an error you leave retrieveItems() without telling Akonadi::ResourceBase that you are done with the task. Therefore, it is assumed the requested item retrieval takes a bit longer (which is not uncommon for resources for remote backends, results typically come in in a result slot connected to a job class for example) and waits until you announce the task is finished.

To confirm a resource is affected by this problem, the "Resource Schedulers" tab of akonadiconsole is very useful (needs to be enabled in the context menu first, causes too much slowdown otherwise). It shows the state of the internal task scheduler of your resource, allowing you to spot stuck tasks.